Hitherto, as a method of determining the compression stroke for clamping the die at the time of injection press forming and injection compression forming, there has been (1) a structure as disclosed in Japanese patent Laid-Open No. 58-167132, Japanese Patent Laid-Open No. 58-167137 and the like in which it is determined by inserting a key between a moveable plate and an end plate or between a fixed plate and a moveable plate, and (2) a structure as disclosed in Japanese Patent Laid-Open No. 60-179218, Japanese Patent Laid-Open No. 60-37297 and the like in which a positioning cylinder is provided between the moveable plate and the fixed plate so that it is determined by the cylinder stroke.
However, according to the above-described structures, only the compression stroke is determined and means to maintain the parallelism between the dies has not been described. As for the parallelism of the dies, parallelism from the compression starting point becomes critical in injection press forming in which the compression stroke is relatively large with respect to that in injection compression forming. If satisfactory parallelism cannot be realized, the action of the molten resin is influenced, causing the quality of the product to become unsatisfactory.
Accordingly, an object of the present invention is to provide an injection press device and a forming method therefor capable of realizing a satisfactory die parallelism and from which products of good quality can thereby be obtained.